357 



Costa Rica Miocenp:— Olsson 



85 



rendered slightly nodulose by the crossing of the longitudinal ribs 

 the penultimate whorl shows 6 or 7 spirals and 14 or 15 on tVie 

 last whorl; the contracted band around the upper part of ihe whorl 

 is nearly free from spirals, but is bordered above as already not- 

 ed b}^ the large, bifid and strongly nodulose spiral cord; base 

 deeply but narrowly umbilicate, spirally sculptured within; col- 

 umella with 3, oblique plications; inner lip with a wide callus, 

 finel}^ pustulated; the outer lip is broken in the type. 



Length 29, diam.eter 20, last whorl 23 mm. 



This is the Miocene analogue of the recent West Coast C. 

 tuberculosa Sowerby. It is probably the species figured by Toula 

 from the Canal Zone and which he compared with C. bullata 

 Sowerby. More recentl}^ Pilsbry and Johnson have described as 

 C. insularis, a Trig 0710 stoma from the Miocene of Santo Dom- 

 ingo and which they consider as possibly identical with Toula' s 

 Isthmian specimen. In their description thej^ mention but 14 

 ribs while toroensis has 2 1 and they relate their species with the 

 Chesapeake Miocene pcrspediva Conrad and the Tampa dcpressa 

 Dall, species which belong to an entirely different group. 



Gatun Stage: 



Toro Cays, Provide?ice of Bocas del Toro, Panama. 



Cancellaria Plummerj, n. sp. Plate 6, figures 2, 3 



Shell thin and delicate, with large, loosely coiled whorls; 

 the whorls are prominently shouldered and deeph^ channeled or 

 excavated along their upper sutures; nucleus of three small, 

 smooth whorls; post-nuclear whorls 4; the sculpture consists of 

 very fine and delicate spiral threads or lines and three rows of 

 slightly elevated spine-like elevations or small tubercles; the 

 larger of these rows is found along the shoulder of the whorls 

 bordering the excavated zone, a smaller on the middle and a 

 small scarcely noticeable one below; on the penultimate whorl, 

 only two rows show and on the upper spire-wliorls but one; the 

 umbilicus is dee]), but narrow: the ir.terior is coiicealed in the 

 matrix . 



